Liquid-level indicator



Patented Nov. 26, 1929 UNITED STATES GEORGE BEYLING, OF MINE-OLA, NEW

YORK, AND FRANK LIMING PLATT, OF

NEW MARKET, NEW JERSEY LIQUID-LEVEL INDICATOR Application filed May 24,

The invention relates to a device for indicating the level of liquids and has for its object the production of a simple device whereby the level of the liquid may be seen at great distance and/or on different levels from the gage or column commonly employed for the purpose.

The reading of the liquid level in a gage or column is diflieult when the observer is it; at a distance away from the gage and/or when he is on a different level.

lit has been attempted in the past to observe the liquid level at a distance by means of reflectors, the result ofwhich is that the 115 column appears small and is visible only when the observer is exactly in the path of the reflected light. This in itself presents a very unsatisfactory result and is of limited use as well as impossible when the gage or column becomes dirty ortranslucent from other causes. a

The general object of the invention is to overcome these difliculties and to produce a ,lisimple meansand method of projectingtlfe 2 image of the liquid level gage with its contained liquid and vapor to any convenient point.

As the refractive indices of a liquid and its vapor, or any other gas vary in general as 80 the direct ratio of the density of the substances, thisinvention utilizes this property to so distort rays of light passing through the column or gage that the projected rays of light passing through the liquid portion 85 of the column will form a differently appearing image than those rays passing through the vapor filled portion of the column. The deflection-of the rays of light striking the meniscus at the surface of the to liquid 'is utilized by a suitable optical or projection system to throw an image on a screen so that as the height of the liquid varies, such variation can be seen on the screen or board placed at a convenient point above 5 or below or horizontally distant from the column orgage;

This image of the meniscus which varies together with the movement of the liquid in the column or gage comprises zones of lights and shadows which we utilize for the 1927. Serial No. 193,867.

purpose of operating light sensitive electric cells for closing or opening an electric circuitas a high and/or low liquidlevel alarm or may be utilized otherwise as conditions may require.

The foregoing and other features of our invention will now be described in connection with the accompanying drawing forming part of this specification in which we have represented our liquid level indicator in its preferred form after which we shall point out in the claims those features which we be lieve to be new and of our joint invention.

In the drawings: 4 Figure 1 is a diagrammatic sketch illustrating the operation of our invention through a preferred form of optical systems. Figure 2 illustrates the image produced by projecting a light source through the liquid level gage.

Figures 3 and 4 show a modified cross section of the liquid level gage. Figure 5 shows the form of image when the "gage as illustrated in Figures 3 or 4 is used.

In the carrying outof our invention we utilize any standardliquid level or gage or column 10 which may be a simple round glass. tube as illustrated in Figures 1 and 2 or it may have any cross section as illustrated in Figures 3 and 4; A source of light 11 by means of a condensing lens 12 is projected through the gage 10. We have indicated the gage substantially half full of liquid by the line 13 whichv is curved showing the usual meniscus found at the top of all liquid confined in a tube. The silhouette of the meniscus is thrown on a mirror 14 and focused by any well known means 15 ona screen or mirror 16 and in the latter event it is finally projected on a screen 17.

The silhouette thus formed is illustrated in Figure 2. The upper half, showing a wide white central line 20 is due to rays of light passing through the glass and vapor or gas above the liquid, while the narrow white central line in the lower half is due to less number of rays of light passing through the liquid. These different widths of the white spaces are due to the difference of refraction of light for the liquid and its vapor or I other gas in the 10,the light rays passing through them g the image. The black central line 22 is caused by the meniscus formed on the top of the liqmd, which cuts It Willztlllls I -onlyserves as .a'li uid levelindicator but-it can beutilized .by relays readily understood that light sensitive cells may of? all the light rays from the light source. This image or silhouette will vary with the sh of. the transparent or translucent tube, wit difl'erent liquids and the angularity of the rays leaving the condenser lens 12. "The typical image shown in" Figure 2 is" that formed when a round gage is used such as a standard water gage.

Should a gage of difierent cross sebtion be used asfor example, one substantiall like that shown in Figure 3 and Figure 4, t e'si1-' houette of the meniscus would resemble that shown in Figure 5.- In this latter case as shown in Figures. 3 and4 rays of light from source 11 will be refracted to a greater 'excircuit ofgivhich shown' is indicated'at 31. When the imagetravelsso that ,one of these cells falls in the path of the light rays the electric current passing through the cell will vary in intensity due to the action of the light rays and this variation in current intensity or other means to control alarms or other uipment It will be be an place within the optical system so as they are placed in zones of li ht and sh ow due to the varying level of the liquid in the column or gage. be seen-that our invention not also maybe utiliz level alarm. u c

Our system is particularly valuable as an as a high and low liquid accessory to modern boilers, hot wells,'confore be unnecessa 7 to change the water' g1 so often or i ever. q

We wish it distinctly understood that our liquid level indicator herein described and illustrated is inthe form in which we desire to construct it but that changes or variations may be madeas ma be convenient or'desirable without departing from the salient features of our invention and we therefore intend the following claims to' cover such modifications as naturally fall within the lines of invention.

1. In a liquid level indicator, a liquid column with its contained liquid and vapor, a source of light projected through the column, an optical system to transmit the image of the water and. vapor, light sensitive electric cells connected to operate a relay located in the zones-of li hts and shadows oi varying a light intensit due to'the 'diflerent refractions of water an vapor, whereby the variation of liquid level will operate the cells and control the relay. V 2. In a liquid level indicator, a liquid col go umnwith its tax- 'ng level of liquid and va-" por, light sensitlve cells spaced apart and controlling the energization of an electrical circuit including a relay means to project rays of light through the liquid and vapor so, that the varying light intensities due to the different refractlons of the liquid, vapor and meniscus will fell upon the li ht sensitive,

cells when the varying level of hquid reaches e location of these, ,7

densersand other liquid containers to indicate the level of the water contained therein.

It iswell known that theliuuidgages become dirty and otherwise trans ucent in which event it is impossible to seethe' level of the liquid with the eye With our invention, however, the transparency of the liquid gage or column does ;not'materially aifect the results ith our invention the column may even be translucent, as it does not materially afl'ect the image produced so long as some of-the as our invention depends upon the variation 7 in refractive indices between the liquid and vapor filledportionof the column and not 1 gpon the transparency of the column itself;

a predetermined point whereby the cells .be- 10o come actively affected controlling their re spective relays. r V

In testimony whereof we aflix our signa tures.

GEORGE REYLING. FRANK LILHNG PLATT.

I no 

